The present invention relates to a bristle article comprising a handle or a holder and at least one bristle formed from a stretched and optionally thermally stabilized plastic monofilament, as well as to a process for the production thereof.
Bristle articles within the meaning of the invention are all appliances or products comprising at least one bristle with a holding or engaging possibility for the hand or a holder or individual bristles or bristles combined into bundles on a carrier. Examples thereof are brushes of all types (flat, rod-shaped, cylindrical), brooms, paint brushes, bristle pads, etc. It is now standard practice to use for such appliances synthetic bristles, which are obtained from plastics of different types by extruding monofilaments. In order to give the monofilaments characteristics similar to those of natural bristles, which are characterized by flexibility and a long-lasting re-righting capacity, following extrusion, the monofilaments are stretched in order to orient the molecular chains in the axial direction and are subsequently stabilized by heat treatment, with the orientation of the molecular chains being virtually frozen in. These monofilaments are then individually or combined in bundles cut to length and fixed to the bristle carrier. Hitherto such fixing has taken place in a largely mechanical manner, in that the bristle carrier is provided with holes in which the bristles or bristle bundles are inserted and are mechanically fixed, e.g. by means of anchor wires, adhesives or the like. Of late the thermoplastic characteristics of the bristles and/or the bristle carrier have been utilized, in that the bristles are welded to the carrier or are inserted in the soft plastic material of the carrier, or are inbedded therein during the injection moulding or expanding of the carrier.
It is also known (DE-B-1 235 856) to anchor the bristles on the bristle carrier, providing the latter with an adhesive and applying the bristles in the electrostatic field. This process is performed in similar manner to the flocking of materials. Bristle articles produced in this way are only suitable for a few functions as a result of the relatively tangled and disordered arrangement of the bristles, which must also be very short and thin. It is also known in connection with an eyelash brush to provide the bristle carrier with certain areas with bristles and to flock same with fibers in the intermediate areas (DE-A-32 31 574, DE-A-34 34 405). It is finally known in connection with hair brushes with injection moulded pins (DE-C-33 17 143) to flock the pins or pin carriers with fibers.
All the aforementioned bristle articles suffer from the disadvantage that, as a result of the construction of the bristles as monofilaments with a smooth surface, they are unable to function in a completely satisfactory manner. If the greatest importance is attached to the cleaning action, the latter is essentially limited to a stripping off or bringing together of the dirt particles by the chafing or pushing bristle ends, which engage with the surface to be cleaned over a short length. This applies with respect to cleaning brushes of all types, such as clothes brushes, tooth brushes, as well as brooms and the like. If the greatest importance is attached to the application or engagement, e.g. application of water to the surface to be cleaned by means of a scrubber, a wet mop, or the like, the application of paints by a paintbrush, the application of cosmetics or the like, as well as hair dyes, etc. in the cosmetic field, then the bristles of the appliances used are designed in such a way that the appliance has a maximum retention capacity for the substance to be applied, which as a rule is brought about by a correspondingly dense bristle coverage. It is also known for this purpose to make use of pitted, grained, corrugated or cross-sectionally profiled bristles.
The aim underlying the present invention resides in providing a construction for bristle articles, which leads to an improvement of each of the aforementioned functions, namely cleaning, application, distribution, etc.
In the case of the aforementioned bristle articles, this aim is realized in that over at least part of its length the bristle is coated with short projecting fibers.
In the simplest case this basic principle provides an appliance or implement having only one bristle, which forms a thin, flexible core with a good righting capacity and has a handle or holder, as well as a coating of projecting fibers surrounding the same outside the handle. Such a fiber-coated bristle can e.g. be used for interdental cleaning in much the same way as a tooth pick or eyelash brush, but several thereof can also be fixed to a holder or carrier.
If e.g. the bristle article comprises a bristle carrier and a plurality of plastic bristles connected thereto, then the invention gives a bristle article, in which the bristles over at least part of the length thereof are coated with short projecting plastic fibers.
It is not important how the bristles are joined to the carrier. For example and as is known per se, the bristles can be moulded in one piece or integrally with the carrier or part thereof. In this case the fiber coating is only applied after the production of the injection moulded part.
However, if as usually the case, the bristle article comprises a bristle carrier and bristles fixed thereto mechanically or thermally and constituted by stretched and optionally thermally stabilized plastic monofilaments, which are optionally combined into bundles, then according to the invention the bristles are coated over part of their length with short projecting plastic fibers.
As a result of the inventive construction in all the aforementioned fundamental variants a bristle is obtained, which is constituted by a core and external flocking. The monofilament forming the core has all the favorable characteristics of a conventional bristle, with regards to the flexibility and the re-righting capacity, while the flocking of short fibers with a much smaller diameter than the monofilament gives the bristle a crusty-rough surface. In the case of the cleaning function, this has the advantageous consequence that the stable bristle core makes it possible to exert the necessary pressure on the surface to be cleaned, while the large number of fibres brings together the dirt particles and also in part stores the particles between them, so that even very fine dirt particles can be taken up. If the main function is the application of a substance, then the fibrous surface structure gives the individual bristle a storage capacity and therefore the brush, paintbrush, mop, etc. a much greater storage capacity, no matter whether fluid or pulverulent substances are involved, which have to be applied or engaged. In this case it is a further characteristic of the application or the like that it can take place much more uniformly than with conventional bristles. However, if the care function is the most important, such as is e.g. the case with hair brushes, hair dye brushes, etc, then the stable or flexible core ensures the necessary dividing up and distribution of the hair, whereas the fine fibers fulfill a care and dyeing function with respect to the individual hairs. Much the same occurs with massage brushes, in which the bristle core performs the vigorous massage action, whereas the fine fibers assists the rubbing function.
The storage capacity of the inventively constructed bristle articles is comprable with that of textile cloths, nonwovens or sponges, without suffering from the hygienic disadvantages thereof, because the freestanding bristles and fibers dry more rapidly and completely.
It is admittedly known from textile technology to flock yarns with fibers. However, yarns are not stable monofilaments and instead constitute an unstable structure formed from a plurality of thinner fibers. The exclusive function of flocking in this case is to give the finished textile product a soft surface and a certain filling effect and velour-like structure. The objective is completely different in the present case.
According to an advantageous construction the fibers are arranged substantially radially on the monofilament, which has a particularly favorable influence on the cleaning and application function.
The monofilament and the fibers can be made from the same or different plastic. In the latter case the fibres are mainly fixed to the monofilament by adhesion, whereas, in the former case they can be imbedded or welded into the monofilament by melting of the monofilament surface and subsequent solidification.
As a result of the inventive flocking of the monofilaments in many applications less bristles per surface unit will be required than in the case of conventional bristle articles. In individual cases it may be adequate if, within a bristle bundle, only individual monofilaments are flocked or if within a bristle coverage of an appliance only individual monofilaments or the monofilaments of some of many bristle bundles are flocked. In this way it is also possible to produce multi functional bristle articles, which, for example, in one area have conventional bristles and in another area flocked bristles.
Finally, an inventively constructed bristle articles can be characterized in that the individual monofilaments are shaped at their ends to form a spherical head by melting the monofilament and the fibers. This construction is, for example, advantageous in the case of hair brushes, where the spherical heads facilitate the penetration into the hair and also lead to no unpleasant reactions, even in the case of sensitive sculp.
Another embodiment of the invention is characterized in that the bristles cut to length and flocked are fixed by their free ends, accompanied by the formation of a camber, to the bristle carrier. This construction has the advantage that the advantageous effects of flocking are also obtained at the bent over bristle ends.
According to a further modification the bristle flocking is cut to a desired outer contour, so that e.g. conical individual or multiple bristles with flocking are obtained.
It is also possible to zonely eliminate the flocking of the bristle by embossing or stamping, in order to obtain fiber-free bristles, which, for example, in the case of a single bristle form a handle or can be shaped to such.
The invention is also directed at a process for producing the aforementioned bristle articles. If the latter in the simplest case comprises a handle or a holder and at least one bristle, then according to the invention the bristle or the endless monofilament from which the bristle is obtained by cutting to length, is coated on its surface, at least zonely with short projecting plastic fibers. It is also possible for the bristle or the endless monofilament from which the bristle is obtained by cutting to length to be coated over its entire length with short projecting plastic fibers and under the action of heat, e.g. by stamping, the fiber coating can be remelted to the core-forming bristle, accompanied by the formation of the handle.
If e.g. in an initially conventional manner plastic monofilaments stabilized by stretching and optionally heat treatment and optionally combined into bundles are fixed to a bristle carrier by mechanical insertion, injection moulding or expansion or by melting the bristle carrier surface and/or the ends of the monofilaments, then according to the invention the surface of said monofilaments is coated with short plastic fibers.
The coating of the monofilaments can take place in that they are provided on the surface with an adhesive and subsequently coated with the fibers. Instead of this and in the case of a corresponding affinity of the material pair constituted by the monofilament and the fibers, it is also possible to heat the surface of the monofilaments to a soft plastic state and then to coat same with the fibres. Instead of this, immediately after the extrusion of the monofilament, the fibres can be applied to the latter.
In the former case the monofilaments are preferably passed through an adhesive bath or mist and are then flocked with fibers, whereas in the latter case the monofilaments are passed through a heating zone and coated therein or behind it with the fibres. Then, as also after the extrusion of the monofilaments, the production of the fiber-coated bristles with the endless monofilaments can take place in a continuous process.
Preferably the coating by flocking takes place in an electrostatic field, independently of the manner of fixing the fibers to the monofilament.
The coated filament can be brought to a particular contour matched to the intended use by subsequent cutting of the fibers, by zonal hot stamping or embossing, or by melting its free end.